text: import { isServer } from './'
  
  export let supportsPassive = false
  if (!isServer) {
    try {
      const opts = {}
      Object.defineProperty(opts, 'passive', {
        get () {
          /* istanbul ignore next */
          supportsPassive = true
        }
      })
      window.addEventListener('test-passive', null, opts)
    } catch (e) {}
  }
  
  export function on (target, event, handler, passive = false) {
    !isServer &&
    target.addEventListener(
      event,
      handler,
      supportsPassive ? { capture: false, passive } : false
    )
  }
  
  export function off (target, event, handler) {
    !isServer && target.removeEventListener(event, handler)
  }
  